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garik1379 [7]
3 years ago
9

!!!!!!!!!!!HELPPPP!!!!!!!!!!! IT'S A TEST!

Chemistry
1 answer:
STALIN [3.7K]3 years ago
3 0
A. Chemical reaction. When the wood burns, new substances form (like ash) and they cannot be changed.

B. Exothermic. When combustion (burning) takes place it is an exothermic reaction. Energy is being released to its surroundings.

hope this helps!
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How many atoms are in one mole of gold? A) 1.97 x 1023 atoms. B) 6.02 x 1023 atoms C) 79 atoms. D) 197 atoms
Kobotan [32]

B. Is the Answer 6.022 * 1023


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3 years ago
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What is the main exception in the atomic radius? Explain.
yarga [219]

Answer:

The atomic radius of atoms generally decreases from left to right across a period. There are some small exceptions, such as the oxygen radius being slightly greater than the nitrogen radius. Within a period, protons are added to the nucleus as electrons are being added to the same principal energy level.

hope this helps!

7 0
3 years ago
If the enthalpy change of a reaction in a flask is δh = +67 kj, what can be said about the reaction?
ziro4ka [17]
Answer : Normally in any chemical reaction, if the enthalpy change i.e. ΔH is positive which means it is greater than zero then it can be called as an Endothermic Reaction.

Whereas, the system under study is absorbing heat that is produced during the reaction. So if  ΔH  is found to be positive then it can be called as endothermic reaction.
3 0
4 years ago
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(a) ions in a certain volume of .20M NaCl (aq) are represented in the box above on the left. in the box above on the right, draw
mamaluj [8]

Answer:

  • The first picture attached is the diagram that accompanies the question.

  • The<u> second picture attached</u> is the diagram with the answer.

Explanation:

In the box on the left there are 8  Cl⁻ ions and 8 Na⁺ ions.

The dissociaton equation for NaCl(aq) is:

  • NaCl (aq) → Na⁺ (aq) + Cl⁻(aq)

The dissociation equation for CaCl₂ (aq)  is:

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A 0.10MCaCl₂ (aq) solution will have half the number of CaCl₂ units as the number of NaCl units in a 0.20M NaCl (aq) solution.

Thus, while the 0.20M NaCl (aq) solution yields 8 ions of Na⁺ and 8 ions of Cl⁻, the 0.10MCaCl₂ (aq) solution will yield 4 ions of Ca²⁺ (half because the concentration if half)  and 8 ions of Cl⁻ (first take half and then multiply by 2 because the dissociation reaction).

Thus, your drawing must show 4 dots representing Ca²⁺ ions and 8 dots representing Cl⁻ ions in the box on the right.

4 0
3 years ago
To the nearest 0.5 mL, what is<br> the water volume in the<br> graduated cylinder?<br> mL?
AnnZ [28]

Answer:

14cm^3

Explanation:

6 0
3 years ago
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